How many 2-digit integers greater than 50 have the property that the sum of the digits is more than double the units digit?

When the units digit equals the tens digit then the sum of the digits of a 2 digit number is double the units digit. In each tens range above 50, numbers below this critical point meet the requirement, numbers above this critical point have a sum LESS than double the units digit.

The applicable numbers are 51-54 (4), 61-65 (5), 71-76 (6), 81-87 (7) and 91-98 (8).

Then there are 4 + 5 + 6 + 7 + 8 = 30 qualifying numbers.